Heat transfer devices using vortex flows to establish cooling gradients have been used in various applications. Known commonly as vortex or Hilsch tubes, compressed air is tangentially directed into an internal counterbore that sets the air stream into a vortex motion. A valve at the end of the tube allows some of the warmed air to escape. The remainder turns back down the tube as a second vortex inside the low pressure area of the larger vortex. The inner vortex looses heat and exhausts through the other end as cold air. Temperatures as low as −50° F. and as high as +260° F. are deemed possible.